SREL Reprint #1941





Water-finding in adult turtles: random search or oriented behaviour?

Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, U.S.A.

Abstract. Aquatic turtles live in a variety of habitats with fluctuating water regimes. Because turtles are long-lived, individuals may repeatedly face the problem of surviving forced emigrations that result from droughts. The hypothesis that adult yellow-bellied pond slider turtles, Trachemys scripta, have a water-finding ability that allows orientation to aquatic habitats in unfamiliar areas was tested. In 1992, 110 pond sliders were trapped and moved beyond their home range to an unfamiliar terrestrial habitat which had a single source of standing water nearby. After an acclimatization period, turtles were released approximately 300 m from the water's edge and out of sight of the water. After 1 h, a heading for each turtle was calculated. Under overcast conditions orientation was random. Under clear conditions, released turtles oriented non-randomly and in the direction of the nearest water, suggesting that adult pond sliders have a water-finding ability. Turtles with the ability to move to another aquatic habitat in a direct, efficient manner should have a selective advantage because reduced exposure to predators, reduced water stress and reduced time away from feeding would lower the cost of overland travel.

SREL Reprint #1941

Yeomans, S.R. 1995. Water-finding in adult turtles: random search or oriented behaviour? Animal Behaviour 49:977-987.

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